. >>> a memorial in connecticut. how some adults tried to stop the elementary school carnage. how others sacrificed their lives. good evening i'm ann notarangelo. a developing story out of san francisco. police have surrounded an apartment building. police say a gunman is barricaded in an apartment. cbs 5 reporter is there. >> reporter: as you can see behind me this whole block is filled with police vehicles, emergency vehicles of just about every type. they've been here all evening. now let's take a look at video. this happened about 6:30 with what police say may have been a domestic disturbance. they di rived on the scene. there was some talk of a weapon. this escalated. so he said there had been some connection. they had some idea there was a weapon. going on that information they brought in the s.w.a.t. team. they brought other people in. >> a neighbor overheard some type of domestic dispute occurring with his next door neighbor. he attempted to make contact with the neighbor. the neighbor made some credible threats that he may potentially have a weapon. the neighbor calle